High blood pressure is defined as a blood pressure >140/80mmHg, and very commonly patients do not have any symptoms.
If you do not have hypertension, it is still important to have your blood pressure periodically checked – normal today does not mean it will always be normal, because our blood pressure can change with age and other individual/environmental factors.
If you have a diagnosis of hypertension, it is important to regularly monitor it, to ensure it is adequately controlled. Home blood pressure machines are readily available and are a good way to keep an eye on your blood pressure, although often an ambulatory blood pressure monitor (a blood pressure monitor that you wear for 24 hours) with a Cardiologist is more informative.